package com.thinkit.bigdata.core.util;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.Serializable;
import java.util.Base64;
import java.util.Random;


/**
 * 生成验证码工具类
 */
public class ValidateCodeUtil {
    //随机产生数字与字母组合的字符串
    private static String randString = "0123456789qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM";
    private static int width = 95;// 图片宽
    private static int height = 25;// 图片高
    private static int lineSize = 40;// 干扰线数量
    private static int stringNum = 4;// 随机产生字符数量
    private static Random random = new Random();

    private static Logger logger = LoggerFactory.getLogger(ValidateCodeUtil.class);

    /**
     * 生成带有随机数字和字母图片
     * Created by lihongli on 2019/01/26
     */
    public static Validate genImgCode() {
        Validate validate = new Validate();
        // BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
        Graphics g = image.getGraphics();// 产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作
        g.fillRect(0, 0, width, height);//图片大小
        g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));//字体大小
        g.setColor(getRandColor(110, 133));//字体颜色
        // 绘制干扰线
        for (int i = 0; i <= lineSize; i++) {
            drowLine(g);
        }
        // 绘制随机字符
        String imgCode = "";
        for (int i = 1; i <= stringNum; i++) {
            imgCode = drowString(g, imgCode, i);
        }
        logger.info("生成的随机验证码为{}", imgCode);
        validate.setValue(imgCode);
        g.dispose();
        try (ByteArrayOutputStream bs = new ByteArrayOutputStream()) {
            // 将内存中的图片通过流动形式输出到客户端
            ImageIO.write(image, "png", bs);
            Base64.Encoder encoder = Base64.getEncoder();
            String base64Str = encoder.encodeToString(bs.toByteArray());
            validate.setBase64Str(base64Str);
        } catch (Exception e) {
            logger.error("图片生成失败", e);
            validate = null;
        }
        return validate;
    }

    /**
     * 获得字体
     *
     * @return
     */
    private static Font getFont() {
        return new Font("Fixedsys", Font.CENTER_BASELINE, 18);
    }

    /**
     * 获得颜色
     *
     * @return
     */
    private static Color getRandColor(int fc, int bc) {
        if (fc > 255)
            fc = 255;
        if (bc > 255)
            bc = 255;
        int r = fc + random.nextInt(bc - fc - 16);
        int g = fc + random.nextInt(bc - fc - 14);
        int b = fc + random.nextInt(bc - fc - 18);
        return new Color(r, g, b);
    }

    /**
     * 绘制字符串
     *
     * @param g
     * @param randomString
     * @param i
     * @return
     */
    private static String drowString(Graphics g, String randomString, int i) {
        g.setFont(getFont());
        g.setColor(new Color(random.nextInt(101), random.nextInt(111), random.nextInt(121)));
        String rand = String.valueOf(getRandomString(random.nextInt(randString.length())));
        randomString += rand;
        g.translate(random.nextInt(3), random.nextInt(3));
        g.drawString(rand, 13 * i, 16);
        return randomString;
    }

    /**
     * 绘制干扰线
     *
     * @param g
     */
    private static void drowLine(Graphics g) {
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        int xl = random.nextInt(13);
        int yl = random.nextInt(15);
        g.drawLine(x, y, x + xl, y + yl);
    }

    /**
     * 获取随机的字符
     *
     * @param num
     * @return
     */
    private static String getRandomString(int num) {
        return String.valueOf(randString.charAt(num));
    }

    public static class Validate implements Serializable {
        private String base64Str;
        private String value;

        public String getBase64Str() {
            return base64Str;
        }

        public void setBase64Str(String base64Str) {
            this.base64Str = base64Str;
        }

        public String getValue() {
            return value;
        }

        public void setValue(String value) {
            this.value = value;
        }
    }
}


